This book is call Descendants written by Melissa de la cruz.
This book is talking about 2 girls and 2 boys named Mal Edie Jay and Carlos they are the children of the bad characters for example Mal is daughter of the evil queen that have killed snow white with an apple. Everyone that are “bad” are living in a island away from the normal world they have everything they need everything they want except they can’t use their power anymore. Mal Edie Jay and Carlos they want to explore the world they have never seen the “real” word. Where they can use their power etc. So they started their adventure and a lot of things happen. I think the theme of this book is that not everyone is bad maybe their parents or family members have done something wrong before but it doesn’t mean that they are bad